Written by James K. Bahcall, DMD, MS, FICD, and Joseph T. Barss, DDS, MS Friday, 31 October 2003 19:00
Technological advances have enhanced the visualization of conventional and surgical endodontic treatment fields. Bahcall and Barss first reported on the use of orascopic visualization in 1999.1 Orascopy is a procedure that uses an orascope or rod-lens endoscope for visualization in the oral cavity. Orascopic endodontics is the use of orascopy for visualization in conventional or surgical endodontic treatment.2 The difference between an orascope and an endoscope is that an orascope utilizes fiber optics and is flexible (Figure 1), whereas the endoscope (Figure 2) utilizes rods of glass and is rigid. The orascope is used to visualize within a root canal system, while the endoscope is used to visualize canal access in conventional endodontic therapy and in surgical endodontic treatment. The orascope and endoscope work in conjunction with a camera, light source, and monitor. Currently, only one orascope/endoscope visual system is available for dental usage, manufactured by Jedmed (Figure 3). The option of a printer or digital recorder can be added to the system for documentation purposes. This report provides an update of endodontic therapy using orascopic visualization.
|Figure 1. Cross-sectional of orascope||Figure 2. An endoscope is a rigid device.|
|Figure 3. The orascopic system (Jedmed, St. Louis, Mo).||Figure 4. Top: the 2.7-mm tip diameter, 70°, 3-cm, rod-lens endoscope. Bottom: the 4-mm tip diameter, 30°, 4-cm length, rod-lens endoscope.|
The use of a rod-lens endoscope in endodontics was first reported in 1979.3 The device was used to help diagnose dental fractures. In 1996, the use of a rodlens endoscope was reported for visualization during conventional and surgical endodontic treatment.4,5 For surgical endodontics, the recommendation was to use an endoscope that is 6 cm in length with a 4.0-mm diameter lens and a 30° angle.6 Since that time, technological advances have yielded smaller endoscopes with increased angulation. Prior to the introduction of these new devices, short endoscopes were fragile, and when the angulation was increased beyond 30°, the images had a fish-eye appearance. Today’s endoscopes are shorter, and when the lens is angled beyond 30°, the fish-eye effect is not present. A 2.7-mm-lens-diameter, 70° angulation, 3-cm-length-rod-lens endoscope and a 4-mm-lens-diameter, 30° angulation, 4-cm-length-rod-lens endoscope are both used for surgical endodontic visualization. These endoscopes use the same camera and monitor. It should be noted that there are many different scope lengths, lens angulations, and diameters in the medical market. The aforementioned endoscopes best fit the ergonomic and logistical considerations for endodontic visualization. The latter configuration (4-mm-lens-diameter, 30° angulation, 4-cm-length-rod-lens endoscope) is also used for conventional endodontic visualization (Figure 4).
When compared to the microscope and loupes, the rod-lens endoscope provides the clinician with greater magnification without loss of focus or depth of field.7
Limited intracanal visualization during endodontic therapy was the catalyst for the development and application of fiber-optic technology in endodontics.1,8 In the past, fiber-optic imaging provided improved ergonomics, but image quality was poor. Today, an improved lens design combined with digital imaging has resulted in excellent visualization and convenient record-keeping. The device is small, lightweight, and flexible. This allows for ease of use in a nonfixed treatment field of vision. It is important to emphasize that image quality from a fiber-optic device is directly correlated with the number of fibers and size of the lens used in an orascope. The greater the amount of visual fibers in conjunction with a larger lens, the more image of a particular treatment field is captured by the camera and hence displayed on the monitor.
|Figure 5. The 0.8-mm tip diameter, 0°, 10K fiber, orascope.|
The fiber-optic orascope used for intracanal visualization has a 0.8-mm-tip-diameter, a 0° lens (a flat lens that does not have any angulation), and the working portion is 15 mm in length (Figure 5). The orascope has 10,000 parallel visual fibers. Each visual fiber is between 3.7 and 5 µm in diameter. To allow for illumination of the treatment field, a ring of larger, light-transmitting fibers surrounds the visual fibers.
GENERAL ORASCOPIC VISUALIZATION TECHNIQUE
Use of the orascope (fiber optic) or endoscope (rodlens) during endodontic therapy requires that the clinician understand that the treatment field environment can have an effect on the image that is generated. Unlike treatment fields visualized with loupes or a microscope, the orascope or endoscope is used in a closer proximity to the field of treatment. This close proximity means that blood and condensation on the scope will have an effect on the clarity of the image. Therefore, use of the orascope or endoscope requires good control of hemostasis and condensation.
|Figure 6. Clinician viewing surgical endodontic field from monitor.||Figure 7. Clinician viewing image from personal LCD monitor.|
It is recommended that 2x to 2.5x loupes be used for visualization prior to the use of the orascope or endoscope.6 Loupes should be used in conventional endodontic treatment to access canals and in surgical endodontic treatment to reflect gingival tissue, remove cortical and medullary bone, and isolate the root end. The clinician should hold the orascope or endoscope during treatment.6 This helps in maintaining good eye/hand coordination during this phase of treatment. The clinician and the assistant(s) view the image from the monitor (Figure 6). The camera has a digital zoom that allows enhanced magnification of the treatment field. A personal LCD monitor (Sony Corp) allows the clinician to view the treatment field without looking at the monitor (Figure 7). Although there is a slight loss of image clarity, the personal LCD improves ergonomics. The clinician can maintain head and body position and need only move the eyes upward to view the image.
ORASCOPIC VISUALIZATION TECHNIQUE FOR CONVENTIONAL ENDODONTIC TREATMENT
|Figure 8. Rod-lens endoscope used in conventional endodontics.||Figure 9. Clinician viewing conventional endodontic field from monitor.|
Once the soft tissue has been removed from the pulp chamber, the 4-mm-lens-diameter, 30° endoscope can be used to examine the pulpal floor when it is necessary to have higher magnification during conventional endodontic treatment (Figure 8). The reason the orascope is not used in this treatment scenario is because the endoscope will provide better image clarity and a wider field of view. The clinician holds the endoscope instead of the dental mirror when using instrumentation or during examination of a conventional endodontic field (Figure 9). When using an instrument or handpiece in conjunction with the endoscope, it is recommended that the endoscope be stabilized by resting it on a cusp tip. If this is not possible due to tooth morphology, a rest in the enamel can be created with a high-speed handpiece and bur.
|Figure 10. Image of intracanal visualization with 0.8-mm orascope.||Figure 11. Placement of antifog solution on the 0.8-mm orascope.|
The 0.8-mm orascope is used to visualize within the canal system (Figure 10). The small fiber-optic size enables the orascope to actually go down into a canal. Prior to the placement of the 0.8-mm fiber-optic scope, the canal must be prepared to a size No. 90 file in the coronal 15 mm of the canal. If the canal is not instrumented to this diameter, a wedging of the probe may occur, damaging some of the fibers within the scope. Appropriate preparation also allows the full 15 mm of the orascope to penetrate within the canal. If a canal is curved, the orascope may not be able to visualize around the curve because of limited flexibility. Also, if the canal is not properly prepared to a size No. 90 file in the coronal 15 mm of the canal, the orascope will not be able to be placed properly within a canal; hence, intracanal visualization will be hindered. The focus and depth of field of an orascope is zero mm to infinity. This allows the orascope to provide imaging of the apical third of the root without actually having to be positioned within this region of the canal.
It is important to note that the canal must be dried prior to usage of the 0.8-mm scope. Although the orascope can be used when sodium hypochlorite is present in the canal, this solution has a high light refractory index. This will result in difficulty visualizing details within the canal. Further, the intracanal environment is relatively warm and humid. Temperature and humidity differences between the dental operatory and the canal can result in moisture condensing on the orascope lens, resulting in fogging. The use of a sterile antifog solution (Jedmed) eliminates this problem (Figure 11).
ORASCOPIC VISUALIZATION TECHNIQUE FOR SURGICAL ENDODONTIC TREATMENT
The 4-mm-lens-diameter, 4-cm-length-rod-lens, 30° endoscope and the 2.7-mm-lens-diameter, 3-cm-length-rod-lens, 70° endoscope are recommended for visualization during surgical endodontic procedures. Prior to placement of a scope, hemostasis within the surgical field must be obtained, since discernible images are not possible if blood is present. The relative warmth of blood will also result in condensation on the lens. As with the orascope, an antifog sterile solution is placed over the lens of the endoscope to help prevent condensation from occurring.
|Figure 12. Application of methylene blue stain to a resected end of a root.|
Methylene blue stain can be used in conjunction with visualization instruments during surgery (Figure 12).9 This stain helps the clinician identify the etiology of the lesion; the defect stains a bluish color, which allows for enhanced visualization with the endoscope. As with conventional endodontic orascopic application, the clinician should hold the endoscope while the assistant retracts gingival tissue and suctions during the surgical procedure.
The 70° angle enables the endoscope to image the resected end(s) of the root(s). The endoscope should be stabilized on bone in such a manner that the clinician has a clear image of the root end. It is not recommended to use the endoscope also to retract gingival tissue. This will inhibit free movement of the endoscope.
It is important to note that the orascope and endoscope not only will allow the clinician to visualize the etiology of the lesion, but will also aid in the surgical phase of the procedure. This is accomplished with ultrasonic instrumentation. Note that the ultrasonic instrument is separate from the endoscope visualization system.
DOCUMENTATION OF PROCEDURES
The recent technological advancements in digital recording have allowed high- quality, digital record-keeping of procedures accomplished with an orascope or endoscope. The digital recordings demonstrate minimal degradation over time, and high-quality paper images can be selectively printed using a digital printer.
Technological advancements in fiber-optic orascopes and rod-lens endoscopes have allowed for the development and evolution of these devices for use in clinical endodontics. The use of orascopy in conventional and surgical endodontic treatment has enabled clinicians to provide patients with improved and more predictable care.
1. Bahcall J, Barss J. Orascopy: Vision for the New Millennium. Dent Today. 1999;18: 66-71.
2. Bahcall JK, Barss JT. Orascopy: a vision for the new millennium: part II. Dent Today. 1999;18:82-85.
3. Detsch SG, Cunningham WT, Langloss JM. Endoscopy as an aid to endodontic diagnosis. J Endod. 1979;5:60-62.
4. Held SA, Kao YH, Wells DW. Endoscope—an endodontic application. J Endod. 1996;22:327-329.
5. Shulman BB, Leung A. Endoscopic surgery: an alternative technique. Dent Today. 1996;15:42-45.
6. Bahcall JK, DiFiore PM, Poulakidas TK. An endoscopic technique for endodontic surgery. J Endod. 1999;25:132-135.
7. Bahcall J, Barss J. Orascope vs. endoscope: a revolution in endodontic visualization. Dentistry. 2001;2:24-27.
8. Bahcall JK, Barss JT. Fiberoptic endoscope usage for intracanal visualization. J Endod. 2001;27:128-129.
9. Cambruzzi JV, Marshall FJ, Pappin JB. Methylene blue dye: an aid to endodontic surgery. J Endod. 1985;11:311-314.
Dr. Barss is a research assistant professor, Cell and Molecular Biology, and PhD fellow in Oral Biology, Northwestern University Medical School. He is a former assistant professor of Endodontics at Northwestern University Dental School.
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